Pumping unit group control method and system

Abstract

The disclosure provides a pumping unit group control method and system, and relates to the technical field of pumping unit control. The pumping unit group control method sets the DC bus of the frequency converter connected to each pumping unit in parallel to the energy storage device, and after obtaining the energy storage state of the energy storage device and the operating state of each pumping unit, controls each pumping unit to be in the upstroke or downstroke according to the operating state, so that the difference between the total power consumption and the total discharge power of all pumping units meets the preset balance condition. Then, the regenerated energy can be recycled through the power consumption and discharge self-circulation between the pumping units. Moreover, the energy storage device can be controlled to charge and discharge according to the energy storage state, so as to recycle the excess regenerated energy or supplement the power consumption of the pumping unit. Therefore, the regenerated energy can be recycled without loss, the purpose of high efficiency and energy saving can be achieved, and the pollution to the power grid or the waste of electric energy can be avoided.

Description

[0001] This disclosure claims priority to Chinese Patent Application No. 202510350703.5, filed on March 24, 2025, entitled "An Elevator Energy-Saving Control System and Control Method", and to Chinese Patent Application No. 2025112284784, filed on August 29, 2025, entitled "An Elevator Energy-Saving Control System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of oil pumping unit control technology, and in particular to a method and system for controlling multiple oil pumping units. Background Technology

[0003] The pumping unit is the core equipment for mechanical oil extraction in oilfields. Its operation is divided into two cyclic stages: the upstroke and the downstroke. The upstroke requires power to be received from its frequency converter, but the regenerative energy generated during the downstroke will discharge to the DC bus of the frequency converter. The traditional solution is to feed this regenerative energy back to the power grid or to convert it into heat through a braking resistor. However, feeding the regenerative energy back to the power grid will pollute the grid, and converting it into heat will result in a large amount of energy waste. Summary of the Invention

[0004] In view of the above problems, this disclosure provides a method and system for controlling a group of oil pumping units to recover and reuse regenerative energy, achieve energy conservation, and avoid pollution to the power grid or waste of electrical energy. The specific solution is as follows:

[0005] The first aspect of this disclosure provides a method for controlling a group of pumping units, used to control the operational behavior of at least two pumping units, wherein the DC bus of the frequency converter connected to each of the pumping units is connected in parallel to an energy storage device; the method for controlling the group of pumping units includes:

[0006] Obtain the energy storage status of the energy storage device and the operating status of each of the oil pumping units;

[0007] Based on the operating states, with the goal of satisfying a preset balance condition for the difference between the total power consumption and total discharge power of all the pumping units, each pumping unit is controlled to be in either the upstroke or downstroke phase; wherein, the total power consumption is the sum of the power consumption of the pumping units in the upstroke phase, and the total discharge power is the sum of the discharge power of the pumping units in the downstroke phase.

[0008] The energy storage device is controlled to charge and discharge according to the energy storage state.

[0009] In one possible implementation, the operating state includes: rated power, stroke, and stroke frequency.

[0010] In one possible implementation, based on the respective operating states, and with the objective of satisfying a preset balance condition between the total power consumption and total discharge power of all the pumping units, each pumping unit is controlled to be in either an upstroke or a downstroke, including:

[0011] For the largest even number of pumping units among those operating in the same state, control half of the pumping units to be in the upstroke and the other half to be in the downstroke.

[0012] For the remaining pumping units where the stroke and stroke frequency are the same, with the goal of the difference between the total power consumption and the total discharge power being less than a preset threshold, some of the pumping units are controlled to be in the upper stroke and some of the pumping units are controlled to be in the lower stroke.

[0013] For the remaining pumping units, with the goal of minimizing the difference between the total power consumption and the total discharge power of each pumping unit when the stroke times overlap, some of the pumping units are controlled to be in the upstroke and some of the pumping units are in the downstroke.

[0014] In one possible implementation, with the goal of the difference between the total power consumption and the total power discharge being less than a preset threshold, the pumping units are controlled to be in the upstroke and the pumping units to be in the downstroke, including:

[0015] according to And M1+M2≤M is used for screening, controlling M1 of the pumping units to be in the upstroke and M2 of the pumping units to be in the downstroke; wherein, P is a preset threshold. i P is the rated power of the i-th pumping unit. j Let M be the rated power of the j-th pumping unit, and M be the number of the remaining pumping units with the same stroke and stroke frequency.

[0016] In one possible implementation, with the objective of minimizing the difference between the total power consumption and the total discharge power of each of the pumping units at overlapping stroke times, the system controls some of the pumping units to be in the upstroke and some to be in the downstroke, including:

[0017] For each of the aforementioned pumping units that overlap at the next hedging time, according to Furthermore, M4 + M5 ≤ M3 is used for screening, controlling M4 of the pumping units to be in the upstroke and M5 of the pumping units to be in the downstroke; wherein, P i P is the rated power of the i-th pumping unit. j P is the rated power of the j-th pumping unit; 余M3 represents the minimum difference between the total power consumption and the total discharge power under all possible combinations of M4 and M5; M3 represents the final number of remaining pumping units.

[0018] In one possible implementation, the pumping units that overlap at the hedging time intervals are, according to... Furthermore, M4 + M5 ≤ M3 is used for screening, controlling M4 of the pumping units to be in the upstroke and M5 of the pumping units to be in the downstroke, including:

[0019] x, which operates simultaneously at the k-th impulse time k The aforementioned oil pumping unit, according to And y + z = x k The selection process involves controlling y of the pumping units to be in the upstroke phase and z of the pumping units to be in the downstroke phase; where P i P is the rated power of the i-th pumping unit. j P is the rated power of the j-th pumping unit; 余 This represents the minimum difference between the total power consumption and the total power discharge, given all possible combinations of y and z values.

[0020] In one possible implementation, the capacity of the energy storage device is according to Configured; where Q is the capacity of the energy storage device, and M6 is the minimum value P of the difference between the total power consumption and the total power discharge. 余 The corresponding number of pumping units, P i f is the rated power of the i-th pumping unit. i Let be the stroke frequency of the i-th pumping unit. These are expansion parameters.

[0021] In one possible implementation, controlling the charging and discharging of the energy storage device according to the energy storage state includes:

[0022] When the energy storage device is in a chargeable and dischargeable state, the energy storage device is controlled to charge, discharge, or not operate according to the discharge demand of each DC bus.

[0023] When the energy storage device is in a non-dischargeable state, the energy storage device is controlled to charge or not operate according to the discharge demand of each DC bus.

[0024] When the energy storage device is not rechargeable, the energy storage device is controlled to discharge or not operate according to the discharge demand of each DC bus.

[0025] In one possible implementation, the pumping unit group control method further includes:

[0026] Adjust the stroke frequency and stroke of each pumping unit according to the total pumping capacity of all the pumping units.

[0027] In one possible implementation, adjusting the stroke frequency and stroke of each of the pumping units based on the total pumping capacity of all the pumping units includes:

[0028] A historical data set is formed based on the total oil extraction volume U of all the aforementioned pumping units;

[0029] Based on the changes in the historical data set, according to Calculate the coefficient of variation of the total pumping volume U. Where i is the latest data index in the historical data set;

[0030] according to Adjust the stroke frequency of each of the aforementioned pumping units; and,

[0031] according to Adjust the stroke of each of the aforementioned pumping units; wherein, This is the stroke adjustment coefficient for the oil pumping unit.

[0032] A second aspect of this disclosure provides a pumping unit group control system, comprising: an energy storage device and an energy-saving controller; wherein,

[0033] The energy storage device is connected to the DC bus of the frequency converter connected to at least two pumping units;

[0034] The energy-saving controller is communicatively connected to the controller of each of the pumping units, and is used to control each pumping unit to be in either the upstroke or downstroke phase according to the operating status of each pumping unit, with the goal of satisfying a preset balance condition between the difference between the total power consumption and the total discharge power of all pumping units; and to control the charging and discharging of the energy storage device according to the energy storage state of the energy storage device; wherein the total power consumption is the sum of the power consumption of the pumping units in the upstroke phase, and the total discharge power is the sum of the discharge power of the pumping units in the downstroke phase.

[0035] In one possible implementation, the operating state includes: rated power, stroke, and stroke frequency;

[0036] When the energy-saving controller controls each of the pumping units to be in the upstroke or downstroke respectively, it is specifically used for: controlling half of the pumping units with the same operating state to be in the upstroke and the other half to be in the downstroke for the largest even number of pumping units; controlling some of the remaining pumping units to be in the upstroke and some to be in the downstroke for the purpose of the difference between the total power consumption and the total discharge power being less than a preset threshold; and controlling some of the remaining pumping units to be in the upstroke and some to be in the downstroke for the purpose of the purpose of minimizing the difference between the total power consumption and the total discharge power of the corresponding pumping units when the stroke times overlap.

[0037] In one possible implementation, the pumping unit group control system further includes: a protection unit;

[0038] After the DC buses are connected in parallel, they are connected to the energy storage device through the protection unit;

[0039] The protection unit is used to provide overcharge and over-discharge protection as well as overload disconnection protection for the energy storage device.

[0040] In one possible implementation, the protection unit includes: a first switch, a second switch, a first diode, and a second diode; wherein,

[0041] The first switch and the second switch are connected in series between the two sides of the protection unit;

[0042] The first diode is connected in parallel with the first switch, and the second diode is connected in parallel with the second switch;

[0043] The first diode is in the direction of the current charging the energy storage device from the DC bus, and the second diode is in the direction of the current discharging the energy storage device from the DC bus.

[0044] The first switch and the second switch are respectively controlled by the energy-saving controller; when the energy storage device is not in a dischargeable state, the first switch is in an open state; when the energy storage device is not in a rechargeable state, the second switch is in an open state.

[0045] In one possible implementation, the protection unit further includes: a third switch and a resistor;

[0046] The third switch and the resistor are connected in series between the two sides of the protection unit;

[0047] The third switch is controlled by the energy-saving controller; the energy-saving controller is also used to: control the third switch to close before the energy storage device and the frequency converter are connected in parallel, and control the third switch to open after the pressure difference on both sides of the protection unit is within a preset range.

[0048] In one possible implementation, the pumping unit group control system further includes: at least two on / off switches; each of the DC buses is connected in parallel through the corresponding on / off switch.

[0049] The pumping unit group control method disclosed herein involves setting up a DC bus of the frequency converter connected to each pumping unit to be connected in parallel to an energy storage device. After acquiring the energy storage status of the energy storage device and the operating status of each pumping unit, and based on the operating status, with the goal of satisfying a preset balance condition between the total power consumption and total discharge power of all pumping units, each pumping unit is controlled to be in either the upstroke or downstroke phase. Furthermore, regenerative energy can be recovered and reused through the self-circulation of power consumption and discharge between the pumping units. Moreover, the charging and discharging of the energy storage device can be controlled according to the energy storage status to recover excess regenerative energy or supplement the power consumption of the pumping units. Therefore, lossless recovery and reuse of regenerative energy can be achieved, achieving high efficiency and energy saving, while also avoiding pollution to the power grid or energy waste. Attached Figure Description

[0050] The features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements and actual parts are not necessarily drawn to scale.

[0051] Figure 1 This is a schematic diagram showing the connection relationship between the pumping unit group control system and each pumping unit provided in an embodiment of this disclosure;

[0052] Figure 2 A flowchart of a pumping unit group control method provided in an embodiment of this disclosure;

[0053] Figure 3 Another flowchart of the pumping unit group control method provided in this disclosure embodiment;

[0054] Figure 4 This is a schematic diagram illustrating the overlap of stroke times at different stroke frequencies, provided in an embodiment of this disclosure.

[0055] Figure 5 A schematic diagram showing the correspondence between the stroke frequency f, stroke S, and working time t of the pumping unit provided in this embodiment of the disclosure;

[0056] Figure 6This is another schematic diagram of the pumping unit group control system provided in the embodiments of this disclosure;

[0057] Figure 7 A circuit diagram of a protection unit in a pumping unit group control system provided in this embodiment of the present disclosure;

[0058] Figure 8 Another circuit diagram of the protection unit in the pumping unit group control system provided in this embodiment of the present disclosure;

[0059] Figure 9 This is another schematic diagram of the pumping unit group control system provided in an embodiment of this disclosure. Detailed Implementation

[0060] The embodiments of this disclosure are described below with reference to the accompanying drawings. The terminology used in the Description of Embodiments section of this disclosure is for illustrative purposes only and is not intended to limit the scope of this disclosure.

[0061] The embodiments of this disclosure are described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure. Those skilled in the art will understand that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of this disclosure are also applicable to similar technical problems.

[0062] The terms “first,” “second,” etc., used in this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the description of embodiments of this disclosure. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of units is not necessarily limited to those units, but may include other units not expressly listed or inherent to those processes, methods, products, or apparatuses.

[0063] The pumping unit is a key piece of equipment in oil extraction, mainly consisting of a power transmission system, a crank-connecting rod-walking beam actuator system, and an auxiliary support system. The power transmission system includes an electric motor, a gearbox, and a braking device. The crank-connecting rod-walking beam actuator system includes a crank, connecting rod, walking beam, pump head, and polished rod-sucker rod string-pump plunger. The auxiliary support system includes a support frame and a base. During operation, the electric motor drives the pump head to move up and down (i.e., upstroke and downstroke), and the pump head, through the polished rod and sucker rod string, drives the plunger of the downhole pump to move up and down, thereby continuously pumping crude oil out of the wellbore.

[0064] During the upstroke, the pumping unit needs to use electricity through the frequency converter, while during the downstroke, regenerative energy is generated and discharged to the DC bus of the frequency converter. Since the power consumption, electricity consumption, regenerative energy power and regenerative energy size of different pumping units will vary, the stroke frequency may also be different. The traditional solution is to feed the regenerative energy back to the grid, but this pollutes the grid or is converted into heat and consumed through the braking resistor, resulting in a large amount of energy waste.

[0065] Therefore, this disclosure provides a method for controlling a group of oil pumping units to recover and reuse regenerative energy, achieving energy conservation and avoiding pollution to the power grid or energy waste. The specific solution is as follows:

[0066] This pumping unit group control method is used to control the operational behavior of at least two pumping units. Figure 1 The example demonstrates controlling the operation of n pumping units, where n is an integer greater than 1; for instance... Figure 1 As shown, the DC bus of the inverter 21 connected to each pumping unit (pumping unit 1 to pumping unit n in the figure) is connected in parallel to the energy storage device 11; specifically, each inverter 21 may include an AC / DC converter (AC / DC1 or AC / DCn in the figure) and a DC / AC converter (DC / AC1 or DC / ACn in the figure); the AC side of the AC / DC converter is used to receive power from other power sources, such as AC power from the mains, and the AC side of the DC / AC converter is used to connect to the motor of the corresponding pumping unit (M1 or Mn in the figure), and the DC side of the AC / DC converter is connected to the DC side of the DC / AC converter through the DC bus; the connection point of each DC bus after parallel connection (including the positive terminal P+ and the negative terminal P-) is connected to the electrode connection terminal (including the positive terminal B+ and the negative terminal B-) of the energy storage device 11.

[0067] The energy storage device 11 can be used to recover the surplus regenerative energy generated by n pumping units, and can also be used to supply power to any number of pumping units, thus playing a role in the recovery and reuse of regenerative energy. At the same time, it can also provide backup power to the pumping units when other power supply methods fail. In addition, the voltage between the energy storage device 11 and the DC bus can be automatically balanced, eliminating the need for an additional DC / DC converter.

[0068] The energy storage device 11 may internally include multiple batteries connected in series and parallel, such as one or at least two battery clusters connected in parallel, each battery cluster including one or at least two battery packs connected in series, and each battery pack including multiple batteries connected in series. An energy-saving controller (not shown in the figure) may be installed internally or externally on the energy storage device 11. This energy-saving controller can collect battery operating data in real time to obtain the operating status of the energy storage device 11. Simultaneously, the energy-saving controller can also communicate with the controllers of each pumping unit (controller 1 to controller n shown in the figure) to obtain the operating data of the pumping units, thereby determining the operating status of the pumping units and controlling their operational behavior. The energy-saving controller and each controller can communicate via a bus; the specific communication method is not limited, such as wired communication like power line carrier communication, or wireless communication like 4G / 5G / 6G / Zigbee, depending on the specific application environment. The energy-saving controller can be used to execute the following pumping unit group control method. Specifically, the pumping unit group control method can be as follows: Figure 2 As shown, it includes:

[0069] S101. Obtain the energy storage status of the energy storage device and the operating status of each pumping unit.

[0070] In this step, the acquisition of energy storage status can be performed in real time or periodically; the acquisition of operating status can also be performed in real time or periodically; and the two can be acquired simultaneously or at different times. In this embodiment, there is no limitation on the acquisition time of the two, which can be determined according to the actual situation.

[0071] S102. Based on each operating state, with the goal of satisfying the preset balance condition between the total power consumption and total discharge power of all pumping units, control each pumping unit to be in either the upstroke or downstroke phase.

[0072] The total power consumption refers to the sum of the power consumption of the pumping units during the upstroke, and the total discharge power refers to the sum of the discharge power of the pumping units during the downstroke. This preset balance condition can mean that the difference between the total power consumption and the total discharge power is very small, for example, within a preset fluctuation range including zero. The upper and lower limits of this preset fluctuation range are not limited and can be determined based on the specific application environment.

[0073] S102 enables self-circulation of electrical discharge between oil pumping units, allowing for the recovery and reuse of regenerative energy.

[0074] S103. Control the charging and discharging of the energy storage device according to the energy storage status.

[0075] S103 enables the energy storage device to recover excess regenerative energy or supplement the power consumption of the oil pumping unit, thereby achieving lossless recovery and reuse of regenerative energy.

[0076] In other words, by utilizing the characteristics of pumping units that consume electricity during the upstroke and discharge during the downstroke, some pumping units can be adjusted to discharge during the downstroke and supply electricity to other pumping units for the upstroke. At the same time, excess discharge from the pumping units can be recovered into the energy storage device and discharged to the pumping units when needed. This achieves a self-circulating cycle of electricity consumption and discharge between pumping units, as well as a large-scale charging and discharging cycle between pumping units, energy storage devices, and other power sources. This solves the problem of the inability to recover and reuse the regenerated energy of pumping units without loss, and achieves the goal of high efficiency and energy saving.

[0077] The pumping unit group control method provided in this embodiment monitors multiple pumping units and adjusts their operating behavior based on the above principle. This enables lossless recovery and reuse of renewable energy, achieving high efficiency and energy saving, and also avoids pollution to the power grid or energy waste.

[0078] Based on the previous embodiment, this embodiment provides an exemplary description of the specific process of the pumping unit group control method. For example, the operating state of the pumping unit may specifically include: rated power, stroke and stroke frequency.

[0079] That is, after S101, the operating states of n pumping units are known to be their rated power P. i Stroke S i and the frequency f i In practical applications, this operating state can also include the oil output R per stroke. i ; where i is any positive integer in [1, n].

[0080] At this point, in S102 of the pumping unit group control method, the step of controlling each pumping unit to be in either the upstroke or downstroke phase, based on its operating state and with the goal of satisfying a preset balance condition between the total power consumption and total discharge power of all pumping units, may specifically include... Figure 3 As shown:

[0081] S201. For the largest even number of pumping units among all pumping units with the same operating state, control half of the pumping units to be in the upstroke and the other half to be in the downstroke.

[0082] Specifically, among all n pumping units, if there exist K pumping units with the same rated power, the same stroke, and the same stroke frequency, where K is any positive integer in (1, n), then for these K pumping units, control K of them... 偶 / 2 pumping units are top stroke, plus K 偶 Two pumping units are bottom-stroke; among them, K 偶 It refers to the largest even number in (1, K], that is, if K is even, then K偶 = K; If K is odd, then K 偶 = K - 1, and the remaining 1 pumping unit is grouped into the remaining pumping units to execute the following S202.

[0083] S202. For each pumping unit with the same stroke and stroke frequency in the remaining pumping units, with the goal of making the difference between the total power consumption and the total power discharge less than a preset threshold, control some of the pumping units to be in the upstroke and some to be in the downstroke.

[0084] In practical applications, the goal that the difference between the total power consumption and the total power discharge is less than the preset threshold can be such that the difference obtained by subtracting the total power discharge from the total power consumption is less than this preset threshold. At this time, power needs to be taken from the energy storage device or other power sources to meet this difference; or, this goal can also be such that the difference obtained by subtracting the total power consumption from the total power discharge is less than this preset threshold. In this case, this difference will charge the energy storage device. In practical applications, no specific limitation is made. Here, an example will be given with the goal that the difference obtained by subtracting the total power discharge from the total power consumption is less than this preset threshold:

[0085] Specifically, after S201, there are n - K 偶 remaining pumping units; among these pumping units, if there are M pumping units with the same stroke, the same stroke frequency, but different rated powers, and M is any positive integer in (1, n - K 偶 , then the operating state data set [P, S, F] of these M pumping units M can be arranged in descending order according to the rated power, and filtered according to and M1 + M2 ≤ M; where, is a preset threshold, such as a very small positive number, P i is the rated power of the i-th pumping unit, P j is the rated power of the j-th pumping unit, M is the number of pumping units with the same stroke and stroke frequency in the remaining pumping units, and both M1 and M2 are positive integers less than M; then, control M1 of these pumping units to be in the upstroke and M2 to be in the downstroke; if M1 + M2 < M, then the remaining M - M1 - M2 pumping units are grouped into the remaining pumping units to execute the following S203.

[0086] S203. For each of the finally remaining pumping units, with the goal of making the difference between the total power consumption and the total power discharge corresponding to each pumping unit at the overlapping stroke times the smallest, control some of the pumping units to be in the upstroke and some to be in the downstroke.

[0087] Similarly, the goal of ensuring the difference between total power consumption and total discharge power is less than a preset threshold can mean either that the difference between total power consumption and total discharge power is less than the preset threshold, or that the difference between total discharge power and total power consumption is less than the preset threshold. In practical applications, no specific limitation is made. The following explanation uses the example of ensuring the difference between total power consumption and total discharge power is less than the preset threshold:

[0088] Specifically, after S202, the final remaining value is M3 = nK. 偶 There are M1-M2 pumping units with different rated power, stroke, and stroke frequency; for these pumping units, at each overlapping stroke time, the operating status dataset [P, S, F] of these M3 pumping units is compiled. M3 Arranged in descending order of rated power, and offsetting the pumping units whose timing overlaps, according to... And M4+M5≤M3 are used for filtering; where P i Let P be the rated power of the i-th pumping unit. j P is the rated power of the j-th pumping unit; 余 M3 represents the minimum difference between total power consumption and total power discharge under all possible combinations of M4 and M5; M3 represents the final number of remaining pumping units; then, M4 pumping units are controlled to be in the upstroke and M5 pumping units are controlled to be in the downstroke.

[0089] Among them, for each pumping unit that overlaps at the hedging time interval, according to And for M4+M5≤M3, a selection process is performed, controlling M4 pumping units to be in the upstroke and M5 pumping units to be in the downstroke. Specifically, this can include: selecting x pumping units operating simultaneously at the k-th stroke time. k One oil pump, according to And y + z = x k Perform the screening; among which, P i Let P be the rated power of the i-th pumping unit. j P is the rated power of the j-th pumping unit; 余 The minimum difference between total power consumption and total power discharge is found among all possible combinations of y and z. Then, y pumping units are controlled to be in the upstroke and z pumping units are controlled to be in the downstroke.

[0090] Schematic diagram of overlapping impulse times at different impulse frequencies is shown below. Figure 4 As shown below, in conjunction with Figure 4 The process of controlling y pumping units to be in the upstroke and z pumping units to be in the downstroke at each stroke time is explained in detail:

[0091] (1) At time t1, there are x-1 pumping units with stroke frequencies from f2 to fx operating simultaneously, that is, at this time k=t1, xk =x-1, then according to Furthermore, y+z=x-1 is used for filtering, and then at time t1, y pumping units are controlled to be in the upstroke and z pumping units to be in the downstroke.

[0092] (2) At time t2, there are x pumping units with stroke frequencies from f1 to fx operating simultaneously, that is, at this time k=t2, x k =x, then according to Furthermore, y+z=x is used for filtering, and then at time t2, y pumping units are controlled to be in the upstroke and z pumping units to be in the downstroke.

[0093] (3) At time t3, there are x-1 pumping units with stroke frequencies from f2 to fx operating simultaneously, that is, at this time k=t3, x k =x-1, then according to Furthermore, y+z=x-1 is used for filtering, and then at time t3, y pumping units are controlled to be in the upstroke and z pumping units to be in the downstroke.

[0094] Figure 4 This is merely one possible schematic diagram for overlapping impulse times at different impulse frequencies, and is not intended as a specific limitation on S203. In practical applications, x k It is acceptable if it is less than or equal to M3 and is an integer.

[0095] The above-mentioned pumping unit group control method can control the operation of the pumping units in real time according to their operating status, so as to realize the self-circulation of power consumption and discharge between the pumping units and minimize the output of the energy storage device.

[0096] Based on the above embodiments, this embodiment provides an example of the specific implementation process of S103 in the pumping unit group control method. For instance, S103 may specifically include: when the energy storage device is in a chargeable and dischargeable state, controlling the energy storage device to charge, discharge, or not operate according to the discharge demand of each DC bus; when the energy storage device is not dischargeable, controlling the energy storage device to charge or not operate according to the discharge demand of each DC bus; when the energy storage device is not rechargeable, controlling the energy storage device to discharge or not operate according to the discharge demand of each DC bus.

[0097] After controlling the operation of each pumping unit via S102, if the energy storage device needs to replenish the power consumption of the pumping unit to the DC bus, it can be controlled to discharge; if the energy storage device needs to store excess regenerative energy on the DC bus, it can be controlled to charge. That is, when the energy storage device is in a chargeable and dischargeable state, it can be controlled to charge, discharge, or not operate according to the power consumption and discharge requirements of each DC bus.

[0098] Furthermore, when the energy storage device is depleted, meaning it can only charge and cannot discharge, the device can be controlled to charge or remain inactive based on the discharge demand of each DC bus. In other words, if each pumping unit has excess regenerative energy, it can charge the energy storage device, but it cannot discharge to the pumping units. Conversely, when the energy storage device is fully charged, meaning it can only discharge and cannot charge, the device can be controlled to discharge or remain inactive based on the discharge demand of each DC bus. In other words, if the energy storage device needs to supplement the power consumption of the pumping units, it can discharge to the pumping units, but if each pumping unit has excess regenerative energy, it cannot charge the energy storage device.

[0099] In practical applications, the above functions can be achieved by directly setting up protection units at the parallel connection points of the energy storage device and each DC bus. For details, please refer to the following system implementation examples.

[0100] Furthermore, based on the above embodiments, the capacity of the energy storage device used in S103 can be configured according to the discharge requirements of each DC bus; specifically:

[0101] The capacity of the energy storage device can be determined according to... Configure the system; where Q is the capacity of the energy storage device; M6 is the minimum value P of the difference between the total power consumption and the total power discharge in S203 above. 余 The corresponding number of pumping units, for example Figure 4 The times t1 and t3 shown both correspond to M6=1; P i f is the rated power of the i-th pumping unit. i Let be the stroke frequency of the i-th pumping unit. These are expansion parameters.

[0102] That is, for the minimum value P of the difference between the total power consumption and the total power discharge in S203 above. 余 The corresponding M6 pumping units can be selected based on their stroke frequency and rated power, according to... Configure the capacity of the energy storage device. Correspondingly, the rated power of the energy storage device is P. 余 + ,in, These are the parameters for expanding power capacity.

[0103] This embodiment does not limit the expansion parameter. The specific value can be determined according to the actual application environment, as long as it can meet the discharge requirements of each DC bus.

[0104] It's worth noting that the pumping unit's specifications, such as stroke and stroke frequency, can change with the pumping unit's operating time and oil output. Specifically, the longer the pumping unit operates, the slower the oil output, and the lower the stroke frequency may be needed to support full tank output with minimal energy consumption. Conversely, if the oil output is insufficient due to longer operating time, the pumping unit must adjust its stroke to achieve maximum pumping efficiency. Therefore, as the pumping unit operates longer, to ensure optimal oil output efficiency, the stroke S and stroke frequency f of the pumping unit will... Figure 5 As shown in the curve, the stroke frequency f gradually decreases and the stroke S tends to increase as the working time t increases.

[0105] That is, based on the above embodiments, the pumping unit group control method may further include: adjusting the stroke frequency and stroke of each pumping unit according to the total pumping volume of all pumping units.

[0106] In practical applications, this process may specifically include: forming a historical data set [U, P, S, f] based on the total pumping volume U of all pumping units. n Based on the changes in this historical dataset, according to Calculate the coefficient of variation of the total pumping volume U. Where i is the latest data index in the historical dataset; according to Adjust the stroke frequency of each pumping unit; and, according to Adjust the stroke of each pumping unit; among them, This is the stroke adjustment coefficient for the oil pumping unit.

[0107] That is, the energy-saving controller in the above embodiment can monitor the total oil extraction volume U of n pumping units in real time and form a historical data set [U, P, S, f]. n Then, based on the changing trend of this historical data set, the coefficient of variation of the total oil extraction volume U is calculated. Then according to the coefficient of variation To adjust the stroke frequency of the pumping unit and the stroke of the pumping unit .

[0108] Through the above adjustments, the pumping unit group control method can adapt to changes in the working time and oil output of the pumping unit, making it highly adaptable.

[0109] Based on the above embodiments, this embodiment provides a pumping unit group control system for controlling the operational behavior of at least two pumping units. Figure 1 The example demonstrates the operation of controlling n pumping units, where n is an integer greater than 1; for instance... Figure 1As shown, the pumping unit group control system includes: an energy storage device 11 and an energy-saving controller (not shown in the figure); wherein:

[0110] The energy storage device 11 is connected to the DC bus of the inverter 21 connected to at least two pumping units (pumping units 1 to n as shown in the figure). Specifically, each inverter 21 may include an AC / DC converter (AC / DC1 or AC / DCn as shown in the figure) and a DC / AC converter (DC / AC1 or DC / ACn as shown in the figure). The AC side of the AC / DC converter is used to receive power from other sources, such as AC power from the mains. The AC side of the DC / AC converter is used to connect to the motor of the corresponding pumping unit (M1 or Mn as shown in the figure). The DC side of the AC / DC converter is connected to the DC side of the DC / AC converter through the DC bus. The connection point of each DC bus after parallel connection (including the positive terminal P+ and the negative terminal P-) is connected to the electrode connection terminal (including the positive terminal B+ and the negative terminal B-) of the energy storage device 11. The energy storage device 11 may include multiple batteries connected in series and parallel, such as one or at least two battery clusters connected in parallel, each battery cluster including one or at least two battery packs connected in series, and each battery pack including multiple batteries connected in series. Each frequency converter 21 and its controller (controller 1 or controller n as shown in the figure) may be integrated into the corresponding pumping unit; this is not limited here. For the specific structure and working principle of the pumping unit, please refer to relevant technologies; details are not elaborated here.

[0111] The energy-saving controller can be integrated inside the energy storage device 11 or located outside the energy storage device 11; this is not limited here. The energy-saving controller communicates with the controllers of each pumping unit (controllers 1 to n as shown in the figure), for example, through a bus. The specific communication method is not limited; it can be wired communication such as power line communication, or wireless communication such as 4G / 5G / 6G / Zigbee, depending on the specific application environment.

[0112] The energy-saving controller is used to control each pumping unit to be in either the upstroke or downstroke phase, based on the operating status of each pumping unit and with the goal of satisfying a preset balance condition between the difference between the total power consumption and the total discharge power of all pumping units; and to control the charging and discharging of the energy storage device according to the energy storage status of the energy storage device; wherein, the total power consumption is the sum of the power consumption of the pumping units in the upstroke phase, and the total discharge power is the sum of the discharge power of the pumping units in the downstroke phase.

[0113] As described in the above embodiments, the operating state includes: rated power, stroke and stroke frequency. Accordingly, when the energy-saving controller controls each pumping unit to be in the upper stroke or lower stroke respectively, it can be used to: (1) control half of the pumping units in the upper stroke and the other half in the lower stroke for the largest even number of pumping units in the same operating state; (2) control some of the remaining pumping units in the upper stroke and some in the lower stroke for the pumping units with the same stroke and stroke frequency, with the goal that the difference between the total power consumption and the total discharge power is less than a preset threshold; (3) control some of the remaining pumping units in the upper stroke and some in the lower stroke for the goal that the difference between the total power consumption and the total discharge power of the corresponding pumping units is minimized when the stroke times overlap.

[0114] Specifically, the energy-saving controller can be used to execute the pumping unit group control method as described in any of the above embodiments; the specific process and principle of the pumping unit group control method can be found in the above embodiments, and will not be repeated here.

[0115] The energy storage device 11 can be used to recover the surplus regenerative energy generated by n pumping units, and can also be used to supply power to any number of pumping units, thus playing a role in the recovery and reuse of regenerative energy. At the same time, it can also provide backup power to the pumping units when other power supply methods fail. In addition, the voltage between the energy storage device 11 and the DC bus can be automatically balanced, eliminating the need for an additional DC / DC converter.

[0116] The pumping unit group control system provided in this embodiment can achieve lossless recovery and reuse of regenerative energy by executing the above-described pumping unit group control method, thereby achieving high efficiency and energy saving, and avoiding pollution to the power grid or waste of electricity. Furthermore, the method described in the above embodiment can also be used to configure the capacity of the energy storage device 11 and adjust the parameters of the pumping units.

[0117] Based on the above embodiments, the pumping unit group control system may further include Figure 6 The protection unit 12 shown in the figure; after each DC bus is connected in parallel, it is connected to the energy storage device 11 through the protection unit 12; the protection unit 12 is used to realize overcharge and over-discharge protection for the energy storage device 11 and overload disconnection protection such as overcurrent / overvoltage for the power circuit between the energy storage device 11 and the pumping unit.

[0118] In practical applications, the protection unit 12 can be installed in the positive branch between the energy storage device 11 and each DC bus parallel connection point (e.g., Figure 6 As shown in the diagram) or in the negative branch (not shown), the following description uses its placement in the positive branch as an example; this protection unit 12 can be as follows Figure 7As shown, the protection unit 12 includes: a first switch S1, a second switch S2, a first diode D1, and a second diode D2; wherein, the first switch S1 and the second switch S2 are connected in series between the two sides of the protection unit 12; the first diode D1 is connected in parallel with the first switch S1, and the second diode D2 is connected in parallel with the second switch S2; the conduction direction of the first diode D1 is the direction of the current charging the energy storage device 11 from the DC bus, and the conduction direction of the second diode D2 is the direction of the current discharging the energy storage device 11 from the DC bus; the first switch S1 and the second switch S2 are respectively controlled by an energy-saving controller; when the energy storage device 11 is not in a dischargeable state, the first switch S1 is in an open state; when the energy storage device 11 is not in a chargeable state, the second switch S2 is in an open state.

[0119] for Figure 7 As shown in the structure, when the energy storage device 11 is in a chargeable and dischargeable state, controlling the first switch S1 to close and the second switch S2 to close allows the energy storage device 11 and the pumping unit to charge, discharge, or not charge or discharge. When the energy storage device 11 is depleted and can only charge, the first switch S1 can be opened and the second switch S2 can be closed, allowing excess regenerative energy generated by each pumping unit to charge the energy storage device 11, but preventing the energy storage device 11 from discharging to the pumping units. When the energy storage device 11 is fully charged and can only discharge, the first switch S1 can be closed and the second switch S2 can be opened, allowing the energy storage device 11 to discharge to the pumping units, but preventing excess regenerative energy from each pumping unit from charging the energy storage device 11.

[0120] Furthermore, such as Figure 8 As shown, the protection unit 12 may further include: a third switch S3 and a resistor R; the third switch S3 and the resistor R are connected in series between the two sides of the protection unit 12; the third switch S3 is controlled by an energy-saving controller; the energy-saving controller is also used to: control the third switch S3 to close before the energy storage device 11 and the frequency converter 21 are connected in parallel, and control the third switch S3 to open after the voltage difference between the two sides of the protection unit is within a preset range.

[0121] Figure 8 The protection unit 12 shown also has a pre-charge function. Specifically, before directly connecting the energy storage device 11 and the pumping unit in parallel, the voltage difference between the two ends is kept within a threshold range to ensure the safe parallel operation of the circuit electrical components. That is, before the passage between the electrode connection terminal of the energy storage device 11 and the parallel connection point of each DC bus is closed, the third switch S3 is controlled to close. When the voltage difference between the two sides of the protection unit 12 is within a preset range, such as less than the parallel operation threshold, the first switch S1 is controlled to close, the second switch S2 is closed, and the third switch S3 is opened. Then, the charging and discharging of the energy storage device 11 can be controlled according to the actual situation.

[0122] In practical applications, this pumping unit group control system may also include Figure 9 (in) Figure 8 (Based on the structure shown in the example) As shown: at least two switching switches (K1 to Kn as shown in the figure); each DC bus is connected in parallel through a corresponding switching switch, and each switching switch can achieve independent disconnection protection control for each pumping unit. Each switching switch can be directly controlled by the energy-saving controller, or it can be indirectly controlled by the energy-saving controller through a corresponding controller. This is not limited here, depending on the specific application environment. The switching switches are set in the transmission branch between the corresponding DC bus and the parallel connection point. Specifically, it may only include a single-pole switch set in the positive transmission branch (e.g., ...). Figure 9 As shown in the diagram, it may include only one pole switch in the negative transmission branch, or it may include one pole switch in the positive transmission branch and another pole switch in the negative transmission branch; there is no limitation here, it depends on the specific application environment; in practical applications, contactors can be used to implement the switches of each pole, but it is not limited to this.

[0123] By implementing the aforementioned pumping unit group control method, this energy-saving controller can control the operation of the pumping units and the protection of the control loops in real time based on the energy storage status and the operating status of the pumping units.

[0124] In addition, the energy-saving controller can draw power directly from the energy storage device 11, or it can draw power from the energy storage device 11 or AC power through an auxiliary power supply module; there is no limitation here, it depends on the specific application environment.

[0125] Furthermore, the energy storage device 11 can also be connected to an AC power source through a conversion module, thereby adding a power transmission path between the energy storage device 11, the AC power source, and each DC bus, which is conducive to realizing a large-scale charging and discharging cycle between the devices.

[0126] Similar or identical parts between the various embodiments in this disclosure can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0127] Those skilled in the art will also recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0128] The above description of the disclosed embodiments shows that the features described in the various embodiments of this disclosure can be substituted for or combined with each other, enabling those skilled in the art to implement or use this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling multiple oil pumping units, characterized in that, Used to control the operation of at least two pumping units, wherein the DC bus of the frequency converter connected to each pumping unit is connected in parallel to the energy storage device; The oil pumping unit group control method includes: The energy storage status of the energy storage device and the operating status of each of the pumping units are obtained, the operating status including: rated power, stroke and stroke frequency; Based on the respective operating states, with the goal of ensuring that the difference between the total power consumption and total discharge power of all the pumping units meets a preset balance condition, each pumping unit is controlled to be in either the upstroke or downstroke phase. The total power consumption is the sum of the power consumption of the pumping units in the upstroke phase, and the total discharge power is the sum of the discharge power of the pumping units in the downstroke phase. This includes controlling half of the pumping units in the upstroke phase and the other half in the downstroke phase for the largest even number of pumping units with the same operating state; and controlling some of the remaining pumping units in the upstroke phase and some in the downstroke phase, based on the respective operating states and with the goal of ensuring that the difference between the total power consumption and the total discharge power is less than a preset threshold. The energy storage device is controlled to charge and discharge according to the energy storage state.

2. The method for controlling multiple pumping units according to claim 1, characterized in that, Based on the respective operating states, with the goal of satisfying a preset balance condition between the total power consumption and total discharge power of all the pumping units, each pumping unit is controlled to be in either the upstroke or downstroke phase, including: For the largest even number of pumping units among those operating in the same state, control half of the pumping units to be in the upstroke and the other half to be in the downstroke. For the remaining pumping units where the stroke and stroke frequency are the same, with the goal of the difference between the total power consumption and the total discharge power being less than a preset threshold, some of the pumping units are controlled to be in the upper stroke and some of the pumping units are controlled to be in the lower stroke. For the remaining pumping units, with the goal of minimizing the difference between the total power consumption and the total discharge power of each pumping unit when the stroke times overlap, some of the pumping units are controlled to be in the upstroke and some of the pumping units are in the downstroke.

3. The method for controlling multiple pumping units according to claim 2, characterized in that, With the goal of the difference between the total power consumption and the total power discharge being less than a preset threshold, the system controls a portion of the pumping units to be in the upstroke and a portion to be in the downstroke, including: according to And M1+M2≤M is used for screening, controlling M1 of the pumping units to be in the upstroke and M2 of the pumping units to be in the downstroke; wherein, P is a preset threshold. i P is the rated power of the i-th pumping unit. j Let M be the rated power of the j-th pumping unit, and M be the number of the remaining pumping units with the same stroke and stroke frequency.

4. The method for controlling multiple pumping units according to claim 2, characterized in that, With the objective of minimizing the difference between the total power consumption and the total discharge power of each pumping unit at overlapping stroke times, the system controls some of the pumping units to be in the upstroke and some to be in the downstroke, including: For each of the aforementioned pumping units that overlap at the next hedging time, according to Furthermore, M4 + M5 ≤ M3 is used for screening, controlling M4 of the pumping units to be in the upstroke and M5 of the pumping units to be in the downstroke; wherein, P i P is the rated power of the i-th pumping unit. j P is the rated power of the j-th pumping unit; 余 M3 represents the minimum difference between the total power consumption and the total discharge power under all possible combinations of M4 and M5; M3 represents the final number of remaining pumping units.

5. The method for controlling multiple oil pumping units according to claim 4, characterized in that, For each of the aforementioned pumping units that overlap at the next hedging time, according to Furthermore, M4 + M5 ≤ M3 is used for screening, controlling M4 of the pumping units to be in the upstroke and M5 of the pumping units to be in the downstroke, including: x, which operates simultaneously at the k-th impulse time k The aforementioned oil pumping unit, according to And y + z = x k The selection process involves controlling y of the pumping units to be in the upstroke phase and z of the pumping units to be in the downstroke phase; where P i P is the rated power of the i-th pumping unit. j P is the rated power of the j-th pumping unit; 余 This represents the minimum difference between the total power consumption and the total power discharge, given all possible combinations of y and z values.

6. The method for controlling multiple pumping units according to claim 4, characterized in that, The capacity of the energy storage device is according to Configured; where Q is the capacity of the energy storage device, and M6 is the minimum value P of the difference between the total power consumption and the total power discharge. 余 The corresponding number of pumping units, P i f is the rated power of the i-th pumping unit. i Let be the stroke frequency of the i-th pumping unit. These are expansion parameters.

7. The method for controlling a group of pumping units according to any one of claims 1 to 6, characterized in that, Controlling the charging and discharging of the energy storage device according to the energy storage state includes: When the energy storage device is in a chargeable and dischargeable state, the energy storage device is controlled to charge, discharge, or not operate according to the discharge demand of each DC bus. When the energy storage device is in a non-dischargeable state, the energy storage device is controlled to charge or not operate according to the discharge demand of each DC bus. When the energy storage device is not rechargeable, the energy storage device is controlled to discharge or not operate according to the discharge demand of each DC bus.

8. The method for controlling a group of pumping units according to any one of claims 1 to 6, characterized in that, The oil pumping unit group control method also includes: Adjust the stroke frequency and stroke of each pumping unit according to the total pumping capacity of all the pumping units.

9. The method for controlling multiple pumping units according to claim 8, characterized in that, Based on the total pumping capacity of all the pumping units, adjust the stroke frequency and stroke of each of the pumping units, including: A historical data set is formed based on the total oil extraction volume U of all the aforementioned pumping units; Based on the changes in the historical data set, according to Calculate the coefficient of variation of the total pumping volume U. Where i is the latest data index in the historical data set; according to Adjust the stroke frequency of each of the aforementioned pumping units; and, according to Adjust the stroke of each of the aforementioned pumping units; wherein, This is the stroke adjustment coefficient for the oil pumping unit.

10. A pumping unit group control system, characterized in that, include: Energy storage devices and energy-saving controllers; among which, The energy storage device is connected to the DC bus of the frequency converter connected to at least two pumping units; The energy-saving controller is communicatively connected to the controllers of each of the pumping units, and is used to control each pumping unit to be in either the upstroke or downstroke phase according to the operating status of each pumping unit, with the goal of ensuring that the difference between the total power consumption and the total discharge power of all pumping units meets a preset balance condition; and to control the charging and discharging of the energy storage device according to the energy storage status of the energy storage device; wherein, the total power consumption is the sum of the power consumption of the pumping units in the upstroke phase, and the total discharge power is the sum of the discharge power of the pumping units in the downstroke phase, and the operating status includes: rated power, stroke, and stroke frequency; including controlling half of the pumping units in the upstroke phase and the other half in the downstroke phase for the largest even number of pumping units with the same operating status; and controlling some of the remaining pumping units in the upstroke phase and some in the downstroke phase according to the operating status of each pumping unit, with the goal of ensuring that the difference between the total power consumption and the total discharge power is less than a preset threshold.

11. The pumping unit group control system according to claim 10, characterized in that, When the energy-saving controller controls each of the pumping units to be in the upstroke or downstroke respectively, it is specifically used for: controlling half of the pumping units with the same operating state to be in the upstroke and the other half to be in the downstroke for the largest even number of pumping units; controlling some of the remaining pumping units to be in the upstroke and some to be in the downstroke for the purpose of the difference between the total power consumption and the total discharge power being less than a preset threshold; and controlling some of the remaining pumping units to be in the upstroke and some to be in the downstroke for the purpose of the purpose of minimizing the difference between the total power consumption and the total discharge power of the corresponding pumping units when the stroke times overlap.

12. The pumping unit group control system according to claim 10 or 11, characterized in that, The pumping unit group control system also includes: a protection unit; After the DC buses are connected in parallel, they are connected to the energy storage device through the protection unit; The protection unit is used to provide overcharge and over-discharge protection as well as overload disconnection protection for the energy storage device.

13. The pumping unit group control system according to claim 12, characterized in that, The protection unit includes: a first switch, a second switch, a first diode, and a second diode; wherein, The first switch and the second switch are connected in series between the two sides of the protection unit; The first diode is connected in parallel with the first switch, and the second diode is connected in parallel with the second switch; The first diode is in the direction of the current charging the energy storage device from the DC bus, and the second diode is in the direction of the current discharging the energy storage device from the DC bus. The first switch and the second switch are respectively controlled by the energy-saving controller; when the energy storage device is in a non-dischargeable state, the first switch is in an open state; when the energy storage device is in a non-rechargeable state, the second switch is in an open state.

14. The pumping unit group control system according to claim 13, characterized in that, The protection unit also includes: a third switch and a resistor; The third switch and the resistor are connected in series between the two sides of the protection unit; The third switch is controlled by the energy-saving controller; the energy-saving controller is also used to: control the third switch to close before the energy storage device and the frequency converter are connected in parallel, and control the third switch to open after the pressure difference on both sides of the protection unit is within a preset range.

15. The pumping unit group control system according to claim 10 or 11, characterized in that, The pumping unit group control system also includes: at least two on / off switches; each of the DC buses is connected in parallel through the corresponding on / off switches.

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